diff --git a/firmware/target/arm/tcc780x/crt0.S b/firmware/target/arm/tcc780x/crt0.S
index f6eb6af..548bb15 100644
--- a/firmware/target/arm/tcc780x/crt0.S
+++ b/firmware/target/arm/tcc780x/crt0.S
@@ -74,7 +74,11 @@ start_loc:
ldr r0, =0xf005a000
ldr r0, [r0, #0x20] /* Read GPIO A */
tst r0, #0x8
- ldrne pc, [pc, #-28] /* Jump to original firmware if HOLD not pressed */
+ ldreq pc, [pc, #-28] /* Jump to original firmware if HOLD pressed */
+ ldr r0, =0xf005a060
+ ldr r0, [r0, #0x20] /* Read GPIO C */
+ tst r0, #0x4000000
+ ldreq pc, [pc, #-28] /* Jump to original firmware if usb connected */
#else
#error No bootup key detection implemented for this target
#endif